style: apply code formatting across backend and frontend (#252)

Apply cargo fmt and prettier formatting to improve code readability.
No functional changes.

Changes:
- Rust: multi-line assertion formatting (gemini_config, env_checker)
- Rust: simplify chained method calls (provider)
- TypeScript: add trailing commas to function parameters (codexProviderPresets)

src-tauri/src/services/env_checker.rs

@@ -159,7 +159,10 @@ mod tests {
     fn test_get_keywords() {
         assert_eq!(get_keywords_for_app("claude"), vec!["ANTHROPIC"]);
         assert_eq!(get_keywords_for_app("codex"), vec!["OPENAI"]);
-        assert_eq!(get_keywords_for_app("gemini"), vec!["GEMINI", "GOOGLE_GEMINI"]);
+        assert_eq!(
+            get_keywords_for_app("gemini"),
+            vec!["GEMINI", "GOOGLE_GEMINI"]
+        );
         assert_eq!(get_keywords_for_app("unknown"), Vec::<&str>::new());
     }
 }